ABSTRACT BACKGROUND: Hyperinflated patients with COPD breathe against an increased elastic load during physical activity. Arm activities are especially demanding. Some pulmonary rehabilitation programs instruct patients to inhale while raising their arms whereas others recommend the opposite. This study aimed to determine the effect of co-ordinating breathing with arm movements on the endurance of a lifting task. METHODS: Participants with COPD and hyperinflation completed two (high and severe intensity) rhythmic constant load lifting tasks to intolerance (tlimit) before and after attending four "teaching" sessions. Participants were randomly assigned to group: 1) taught to inhale during the lift; 2) taught to exhale during the lift, or; 3) sham (unconstrained coordination). RESULTS: 36 participants (FEV1 [SD] = 34 [13] %predicted; FEV1/FVC = 33 [10]%; thoracic gas volume = 179 [44] %predicted) completed the study. There was an effect of group on the change in tlimit (p &lt; 0.01) regardless of intensity (p=0.47). The change in tlimit in the 'exhalation' group was greater than both the 'sham' (difference [95%CI] = 2.82 [0.21 to 5.44] min; p &lt; 0.05) and 'inhalation' (difference = 3.29 [0.65 to 5.92] min; p &lt; 0.05) groups at the high intensity. There was no difference in the change in tlimit between the 'inhalation' and 'sham' groups. CONCLUSION: A specific breathing strategy, exhalation during the lift, improved task performance. Co-ordinating exhalation with lifting may be of value to hyperinflated patients with COPD engaged in arm and shoulder training exercise or daily activities that involve arm elevation. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00836108.